ITaskItem

The ITaskItem interface is implemented in EXPLORER.EXE
by a class that is named internally as CTaskItem (which
the Windows 10 implementation derives to CWindowTaskItem
and CImmersiveTaskItem). The interface is thought to
be used only within EXPLORER.

Please note that the interface is not only internal to EXPLORER.EXE but is highly
variable from one Windows version to another. At least Microsoft has changed the
IID each time the interface has changed substantively, which has not always been
its practice with COM interfaces in the shell. Beware, however, that these notes
have been prepared only from inspection of the original release of each version.

Interface

IID

Versions

ITaskItem

{93179D36-69BA-4020-952E-1FDA5F0949A9}

6.1 only

{D81D7F0B-67FA-4FCC-98A6-956361DC3608}

6.2 to 6.3

{7541500A-8E26-45A9-B917-ECC3942192B4}

10.0 only

No evidence is known that Microsoft defines the conventional symbol
IID_ITaskItem for this interface’s IID. Microsoft’s
names and types for the ITaskItem methods are known
from the public symbol files for EXPLORER.EXE. The presentation here follows the
ordering of the virtual function table after the IUnknown
methods.

Among the types that can be passed as arguments or be returned or be produced
at addresses that are passed as arguments, an undocumented _TBPSTATE
and tagTHUMBBUTTON32 are represented above by type definitions
which follow age-old Microsoft conventions: